11-08 :: August 2011

nanotimes News in Brief

exquisite precision. “The heart of our device is an array made of graphene ribbons only millionths of a meter wide,” says Feng Wang of Berkeley Lab’s Materials Sciences Division, who is also an assistant professor of physics at UC Berkeley, and who led the research team. “By varying the width of the ribbons and the concentration of charge carriers in them, we can control the collective oscillations of electrons in the microribbons.”

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Alex Zettl, Y. Ron Shen & Feng Wang: Graphene plasmo- nics for tunable terahertz metamaterials, In: Nature Na- notechnology AOP, September 04, 2011, DOI:10.1038/ nnano.2011.146: http://dx.doi.org/ 10.1038/nnano.2011.146

The German Advisory Council on the Environment (SRU) released a report entitled Precautionary Stra- tegies for Managing Nanomaterials, which makes recommendations for a “responsible and precautio- nary development” of nanotechnology.

http://www.umweltrat.de/SharedDocs/Downloads/

EN/02_Special_Reports/2011_09_Precautionary_Stra- tegies_for_managing_Nanomaterials_KFE.pdf?__ blob=publicationFile

Image: The graphene microribbon array can be tuned in three ways. Varying the width of the ribbons changes plasmon resonant frequency and absorbs corresponding frequencies of terahertz light. Plas- mon response is much stronger when there is a dense concentration of charge carriers (electrons or holes), controlled by varying the top gate vol- tage. Finally, light polarized perpendicularly to the ribbons is strongly absorbed at the plasmon reso- nant frequency, while parallel polarization shows no such response. © LBL

Long Ju, Baisong Geng, Jason Horng, Caglar Girit, Micha- el Martin, Zhao Hao, Hans A. Bechtel, Xiaogan Liang,

A group of scientists from the University of Gothen- burg and the Royal Institute of Technology (KTH), Sweden, have become the first group in the world to demonstrate that theories about nanoscale spin waves agree with observations. This opens the way to replacing microwave technology in many applications.

M. Madami, S. Bonetti, G. Consolo, S. Tacchi, G. Car- lotti, G. Gubbiotti, F. B. Mancoff, M. A. Yar, J. Åkerman: Direct observation of a propagating spin wave induced by spin-transfer torque, In: Nature Nanotechnology AOP, August 28, 2011, DOI:10.1038/nnano.2011.140: http://dx.doi.org/10.1038/nnano.2011.140